The invention relates to dilatation balloon devices which are introduced into body passageways for the purpose of dilating a collapsed portion of the passageway. In particular, the invention provides devices capable of use in balloon angioplasty.
Typically, the balloon, placed at the distal end of a flexible shaft, enters the body by means of a catheter. The balloon is then positioned in the affected region and inflated, thereby forcing the obstructed way open. The balloon may then be deflated and the device withdrawn back through a catheter and from the body.
It is advantageous for such devices to provide a small diameter profile when the balloon is deflated to allow atraumatic advance through body passageways and for positioning the balloon in the region of narrowing lesions. Angioplasty of smaller arteries, such as the coronary artery, typically requires balloons of 3 mm inflated diameter or less, which, when deflated and collapsed about a shaft, can be introduced through diagnostic catheters. For larger arteries, such as the renal artery or popliteal artery, balloons of larger inflated diameter, up to as large as 8 mm, are required for angioplasty treatment; the lesions of these arteries, however, are not necessarily larger. Larger balloons, when deflated, tend to produce larger diameter profiles, thereby inhibiting their use across narrow lesions and requiring larger diameter introduction catheters.